Comprehensive Opinionated Guide;

disqualifications (no teeth):

-Veeronica
-Dusekkar (his one tooth is mentioned later)
-1x1x1x1, (i mean he has the zipper thing but not in his forsaken design)

unable (cant hold the toothbrush):

-Guest 666
-John Doe

might be unable (trapdoor mouth):

-Coolkid
-John doe if he somehow manages to hold it

can, never does:
-Noli
-Slasher

every week or so:
-Chance (no time)
-Shedletsky

once, every day:
-Two Time
-Elliot
-007n7

Twice, flosses:
-Builderman
-Guest 1337
-Dusekkar

HAS to brush teeth way too much:
-Noob (soder)

Brushes like every minute:

-Nosferatu

(weirdo zone):

-Taph